The invention relates to a method of producing a connection of a structural component having at least one retaining element, with a structural element.
Commonly employed methods for joining parts comprise detachable connections, on the one hand, and the group of undetachable joints, on the other. Basically, undetachable joints are actually detachable as well, though only with considerable expenditure. However, if such an undetachable connection is, for example a welded joint or a riveted connection, such detachmant leads to complete destruction of the joints and, in most cases, to mechanical damage of the zones where the components were joined before.
Detachable connections, which are in most cases screw connections or clamped joints or the like, are labor- and consequently cost-intensiveboth in regard to their manufacture and installation and particularly in dismantling work when the connecting means need to be removed.
The invention is based on the problem of producing at favorable cost a connection that can be detached again at low labor expenditure.
Said problem is solved according to the invention in that at least one intermediate holding means is formed by means of an adhesive and curing, pourable compound on a surface disposed in the zone of connection, such intermediate holding means being engageable in an actively holding connection with at least one holding element of the structural component.
It is a special feature of the method specified herein that the structural component is not directly joined with the structural element, but rather connected with the latter via the intermediate holding means, whereby the latter is formed on site in a way essential to the invention, i.e., in the zone of connection by pouring, pressing or injecting of the liquid, curing pourable compound.
The present method may be implemented by employing the following procedure: The structural component is placed against the structural element in a predetermined position and subsequently caused to participate in the development of the intermediate holding means made of pourable compound, i.e., by participating in the shaping of the latter into the intermediate holding means.
The intermediate holding means shaped on site from pourable compound in the zone of connection is joined with the structural element because of its adhesion. For the purpose of reinforcing said connection, the intermediate holding means is preferably glued to the structural element by adding the pourable compoundxe2x80x94which is still more or less liquidxe2x80x94to an adhesive applied to the zone of connection. The cured intermediate holding means can then be brought into an actively retaining connection, so that the structural component finally can be easily and simply joined with the structural element.
The intermediate holding element can be cast, for example from a pourable compound. Such pourable compound is in the liquid state while it is being cast.
According to a further development of the invention, provision is made that the intermediate holding means is extruded from a pourable compound. By extruding, for example a pasty pourable compound, i.e. an extrusion compound, it is possible to shape an intermediate holding means and place the latter onto a structural element. Furthermore, no additional mold parts are advantageously needed when the intermediate holding means is extruded for forming the mold for shaping the intermediate holding means.
According to another further development of the invention, rather the structural component and the structural element for a space for receiving the extruded pourable compound as the intermediate holding means is being shaped. Such receiving space is preferably completely formed by the structural component and the structural element. For example, the structural component is attachable to the structural element in the predetermined position, forming at the same time such a receiving space in this way. The receiving space is formed, for example in the form of a cavity, a groove, a deepening or the like, into which the extruded pourable compound is applied or filled for forming the intermediate holding means. The extruded pourable compound is applied or filled by means of an extrusion nozzle which, for example, is designed in the form of a wide-slot nozzle. Such a wide-slot nozzle can be dimensioned in such a way that it moves across and covers the entire receiving space formed by the structural component and the structural element, so that one single movement over said receiving space with simultaneous application of the pourable compound fills the receiving space with the extruded pourable compound, e.g. completely. The extruded pourable compound subsequently cures, forming the intermediate holding means, which then joins the structural component and the structural element with one another. Also, the structural component and the structural element may form such a receiving space for a liquid pourable compound to be cast as well. Said structural elements may be supported in this connection in such a way that the receiving space formed is arranged in such a way that the casting compound poured into said space will not drain from the latter.
The structural component and the structural element may consist of all sorts of different materials such as, for example metal, glass, wood, plastic, or elastomer. Therefore, the method as defined by the invention also offers the advantage that all kinds of different materials can be joined with each other without any problems.
A two-component polyurethane, for example, can be used as the pourable compound, so that the intermediate holding means formed from such a material cures chemically. Also, a single-component polyurethane reacting with moisture is usable as well. However, also other curing materials can be employed, for example those setting through a thermal treatment.
An actively holding connection between the structural component and the intermediate holding means formed from the pourable compound is obtained according to the invention by providing one or several holding elements of the structural component with a shape permitting such holding elements to be joined with the intermediate holding means by clamping, interlocking or the like. For example, as holding elements, usable cavities in the structural component could be filled by pouring or extrusion when the pourable compound is applied, so that upon curing of the intermediate holding means, the latter has been joined with the structural component through interclamping with the latter. Also, pourable compounds can be poured around projections, ledges, noses, ribs and the like present on the structural component, so that such holding elements are received in the cured intermediate holding means and thus clamped as well. Since the finished, its function developing intermediate holding means is glued to the structural element, the structural component and the structural element are finally solidly joined with each other via the extruded or poured intermediate holding means. A mechanical connection exists in this joint between the structural component and the intermediate holding means, which connection, with suitable geometry of the holding elements, also can be detached again, if necessary, namely if either lugs molded on the intermediate holding means can be easily pulled out again from cavities in the structural component, or if projections, feet, ribs and the like holding elements of the structural component, such elements having the pourable compound poured around them, are pulled from the intermediate holding means.
With particular advantage, the method as defined by the invention permits alternative designs for actively retaining connections in that the joint between the structural component and the structural element is either completed or finished following extrusion or pouring of the pourable compound, or in that suitable shapes are formed in the intermediate holding means permitting easy assembly of the structural component and the structural element by bringing the cured intermediate holding means, which is solidly glued to the structural element, into an actively retaining connection with the holding elements on the structural component. For example, locking strips as holding elements can be arrested in undercuts or the like receptacles of the intermediate holding means, such undercuts or the like receptables being adapted to and matching such locking strips in terms of shape,
Various corresponding shapes effecting a positive lock are basically applicable for obtaining an actively retaining connection between the structural component and the intermediate holding means.
It is particularly advantageous if a material is used for the pourable compound which has properties that are contrasting the properties of the given structural component upon curing with respect to hardness and elasticity, For example, if the structural component consists of a hard material such as metal or the like, it is advantageous to select for the pourable compound a material which still remains elastic upon curing. The structural components or their holding elements then can be pulled from the intermediate holding means cured from the pourable compound because the leastic material of the latter is capable of deformation. On the other hand, it is advantageous to employ a harder pourable compound if the structural component consists of a soft material, for example an elastomer. When the structural component and the structural element are separated, the holding element of the structural component will then deform because the latter is softer than the intermediate holding means.
The structural component and its holding element are preferably produced jointly in one working step and thereafter joined with the structural element via the intermediate holding means. Preferably moss rubber is used as material for the structural component. Moss rubber has elastic properties which are advantageous in certain cases of application of the connection as defined by the invention. For example, moss rubber is suitable for applications of structural components in the field of sealing technology, where a relatively soft elastomer component, for example, is used as a sealing lip because noise caused by friction and in particular squeaking noise is prevented because of the excellent elasticity. A material harder than moos rubber, for example EPDM is employed as material for the holding element.